PCB 4233 IMMUNOLOGY EXAM 1QUESTIONS WITH COMPLETE ANSWERS
Course
PCB 4233
1. Innate Immunity
Which component of the immune system provides the first line of defense against pathogens?
A. B lymphocytes
B. T lymphocytes
C. Innate immune system
D. Adaptive immune system
Answer:
C. Innate immune system
Explanation:
The innate immune system acts immediately against pathogens using barriers such as skin,
mucus, phagocytes, and inflammation.
2. Antibodies
Which immunoglobulin is most abundant in human blood plasma?
A. IgA
B. IgD
C. IgE
D. IgG
Answer:
D. IgG
Explanation:
IgG is the most common antibody in circulation and plays a major role in long-term immunity
and secondary immune responses.
3. Antigen Presentation
Which cells are considered professional antigen-presenting cells (APCs)?
A. Red blood cells
B. Platelets
,C. Dendritic cells
D. Muscle cells
Answer:
C. Dendritic cells
Explanation:
Dendritic cells process antigens and present them to T cells using MHC molecules, initiating
adaptive immune responses.
4. Major Histocompatibility Complex (MHC)
MHC class I molecules primarily present antigens to:
A. B cells
B. Helper T cells (CD4+)
C. Cytotoxic T cells (CD8+)
D. Neutrophils
Answer:
C. Cytotoxic T cells (CD8+)
Explanation:
MHC class I molecules present intracellular antigens to CD8+ T cells, which destroy infected
cells.
5. Complement System
The complement system mainly functions to:
A. Produce antibodies
B. Increase oxygen transport
C. Enhance pathogen destruction and inflammation
D. Regulate blood pressure
Answer:
C. Enhance pathogen destruction and inflammation
Explanation:
The complement system promotes opsonization, inflammation, and direct lysis of pathogens.
, 6. Immunology Formula
Ag+Ab→Immune ComplexAg+Ab\rightarrow Immune\ ComplexAg+Ab→Immune Complex
The equation above represents:
A. Blood clotting
B. Antigen-antibody binding
C. Protein synthesis
D. Cell respiration
Answer:
B. Antigen-antibody binding
Explanation:
An immune complex forms when an antibody specifically binds to an antigen.
7. B Cells
The primary function of B lymphocytes is to:
A. Destroy infected cells directly
B. Produce antibodies
C. Engulf bacteria
D. Produce histamine
Answer:
B. Produce antibodies
Explanation:
Activated B cells differentiate into plasma cells that secrete antibodies.
8. T Cells
Helper T cells are identified by which surface marker?
A. CD8
B. CD4
C. CD16
D. CD21
Course
PCB 4233
1. Innate Immunity
Which component of the immune system provides the first line of defense against pathogens?
A. B lymphocytes
B. T lymphocytes
C. Innate immune system
D. Adaptive immune system
Answer:
C. Innate immune system
Explanation:
The innate immune system acts immediately against pathogens using barriers such as skin,
mucus, phagocytes, and inflammation.
2. Antibodies
Which immunoglobulin is most abundant in human blood plasma?
A. IgA
B. IgD
C. IgE
D. IgG
Answer:
D. IgG
Explanation:
IgG is the most common antibody in circulation and plays a major role in long-term immunity
and secondary immune responses.
3. Antigen Presentation
Which cells are considered professional antigen-presenting cells (APCs)?
A. Red blood cells
B. Platelets
,C. Dendritic cells
D. Muscle cells
Answer:
C. Dendritic cells
Explanation:
Dendritic cells process antigens and present them to T cells using MHC molecules, initiating
adaptive immune responses.
4. Major Histocompatibility Complex (MHC)
MHC class I molecules primarily present antigens to:
A. B cells
B. Helper T cells (CD4+)
C. Cytotoxic T cells (CD8+)
D. Neutrophils
Answer:
C. Cytotoxic T cells (CD8+)
Explanation:
MHC class I molecules present intracellular antigens to CD8+ T cells, which destroy infected
cells.
5. Complement System
The complement system mainly functions to:
A. Produce antibodies
B. Increase oxygen transport
C. Enhance pathogen destruction and inflammation
D. Regulate blood pressure
Answer:
C. Enhance pathogen destruction and inflammation
Explanation:
The complement system promotes opsonization, inflammation, and direct lysis of pathogens.
, 6. Immunology Formula
Ag+Ab→Immune ComplexAg+Ab\rightarrow Immune\ ComplexAg+Ab→Immune Complex
The equation above represents:
A. Blood clotting
B. Antigen-antibody binding
C. Protein synthesis
D. Cell respiration
Answer:
B. Antigen-antibody binding
Explanation:
An immune complex forms when an antibody specifically binds to an antigen.
7. B Cells
The primary function of B lymphocytes is to:
A. Destroy infected cells directly
B. Produce antibodies
C. Engulf bacteria
D. Produce histamine
Answer:
B. Produce antibodies
Explanation:
Activated B cells differentiate into plasma cells that secrete antibodies.
8. T Cells
Helper T cells are identified by which surface marker?
A. CD8
B. CD4
C. CD16
D. CD21
